1. Field of the Invention
The present invention relates to railway signal transmission, and particularly, to a bond pin assembly for connecting a connection cable with a rail.
2. Description of the Related Art
In a railway system of the related art, both railway signals and propulsion currents of electric circuits are transmitted through a rail. As shown in FIG. 1, a power supply 103, a connection cable 102, a rail 104, and a wheel 105 form a closed circuit when a wheel passes through a certain position of the rail 104. In this closed circuit, usually, the connection cable 102 is fixed to the rail 104 with a bond pin 101, which is a part of the closed circuit.
In the related art, the plug pin 101 usually includes a truncated-cone portion and a cylindrical portion. The truncated-cone portion is provided at the waist of the rail 104, that is, at a middle height of the rail 104, and is connected to a signal generator. Usually, the smaller end of the truncated-cone portion is inserted into a through hole of the rail 104 by hammering. The cylindrical portion is connected with one end of the connection cable 102 by soldering. The other end of the connection cable 102 is led to the inside of the power supply 103, and is connected with various elements by screws.
In the related art, there exist the following problems in fixing the connection cables.
1. The plug pin and the rail are connected by inserting the truncated-cone portion of the plug pin into the cylindrical through hole of the rail. However, when the truncated-cone portion is inserted into the cylindrical through hole, only parts of the truncated-cone portion is in contact with the wall of the cylindrical through hole, and there exist gaps in the through hole of the rail. When a train passes, the rail vibrates up and down strongly and highly frequently, and this may cause the plug pin loose, and as a result, the resistance of the closed circuit increases, and this causes signals abnormal.
2. When one hammers the end of the truncated-cone portion to insert the same into the through hole of the rail, if one hammers the plug pin too strongly, the plug pin may be damaged and this may cause cracks in the plug pin. The cracks may become bigger and bigger under strong vibration when a train passes, consequently, the damaged portion of the plug pin may peel off, and this is a big hidden danger for safety. In addition, the peeled-off portion of the plug pin lies in the gap between the rail and the plug pin, and may becomes rusty because of long term erosion of rain water, as a results, the rust may firmly adhere the plug pin to the rail inside the through hole, and this results in difficulty when disassembling and exchanging the plug pin.
In case the plug pin cannot be disassembled manually, one has to use dedicated pin puller to forcibly pull the plug pin out.